David Schwab, a research scientist at the University of Michigan's Water Center, looked at six different scenarios — and all spelled a catastrophe for the Great Lakes.

by Keith Matheny, McClatchy News Service
/
July 11, 2014

A rupture of 61-year-old, underwater oil pipelines running through the Straits of Mackinac would be “the worst possible place” for a spill on the Great Lakes, with catastrophic results, according to a University of Michigan researcher studying potential impacts of a spill.

David Schwab, a research scientist at the U-M Water Center recently retired from the National Oceanic and Atmospheric Administration where he studied Great Lakes water flows and dynamics for more than 30 years. He’s the author of a new study done in collaboration with the National Wildlife Federation looking at different scenarios for potential oil spills in the Straits from Canadian oil transport giant Enbridge’s Line 5.

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“I can’t think — in my experience — of another place on the Great Lakes where an oil spill would have as wide an area of impact, in as short of time, as at the Straits of Mackinac,” Schwab said.

Line 5 is a set of two oil pipelines that runs from Superior, Wis., through the Upper Peninsula, underwater through the Straits and then down through the Lower Peninsula before connecting to a hub in Sarnia, Ontario. The lines transport about 23 million gallons of oil and other petroleum products such as natural gas liquids through the Straits daily.

A July 2010 spill near Marshall caused by a ruptured Enbridge pipeline, and concerns about the underwater pipeline through the Straits, already has prompted state and federal scrutiny. Michigan’s U.S. Sens. Carl Levin and Debbie Stabenow have sought information on Line 5, as have several members of Congress. And state Attorney General Bill Schuette and Michigan Department of Environmental Quality Director Dan Wyant late last month announced they will cochair a multiagency government task force to look at petroleum pipelines and the health, safety and environmental issues they potentially pose in Michigan.

Schwab looked at six different scenarios — and all spelled a catastrophe for the lakes. That’s due in large part to the Straits of Mackinac being “really a strange place on the Great Lakes,” he said. The strength of water flowing through the Straits is 20 times the amount necessary to keep lakes Michigan and Huron at the same water level, he said. And the flows go in both directions — sometimes from Michigan to Huron; sometimes from Huron to Michigan — and change directions every few days.

Schwab created six animation models looking at what would happen if Line 5 ruptured at the northern, middle and southern end of the Straits — both at times when the water is flowing into Lake Michigan and when it’s flowing into Lake Huron. His projection was for a 1 million gallon oil spill lasting 12 hours.

“One million gallons is conservatively the amount of oil that resides in the pipelines in the Straits at any time,” he said.

The spill scenarios show that depending on current directions, a spill could be transported eastward into Lake Huron, westward into Lake Michigan, and move back and forth through the Straits several times. Shoreline areas most impacted would be Mackinac Island, Bois Blanc Island and the Lake Huron shoreline east of Mackinaw City. Contamination could spread as far west as Beaver Island in Lake Michigan to Rogers City in Lake Huron, the study found.

“What this report shows is a significant oil spill in the Straits would be an ecological disaster for the Great Lakes,” said Andy Buchsbaum, regional executive director for the National Wildlife Federation. “It would severely impact shipping and tourism.”

Such a spill would severely damage “the Great Lakes brand,” Buchsbaum said. “The Straits of Mackinac are iconic. They are what many people think of when they think of the Great Lakes. It would be a death blow for the Great Lakes ecology and economy.”

Line 5 is older than an Enbridge oil pipeline that ruptured near Marshall in July 2010, causing the largest inland oil spill in U.S. history and necessitating a $1 billion cleanup of the Kalamazoo River and Talmadge Creek that is still not complete.

Enbridge spokesman Jason Manshum said the company shares the National Wildlife Federation’s “views on the critical nature of the Great Lakes ecosystem in general, and the Straits in particular.” This new report will advance “continued and meaningful discussion on pipeline safety in the Straits,” he added.

Manshum noted that Line 5 “has been incident-free since it was constructed in 1953, and through even greater oversight, the use of new technology and ensuring all risks are monitored and, where necessary, mitigated, Enbridge is committd to maintaining this incident-free record into the future.”